Network architecture for data communication

ABSTRACT

This invention relates to a network architecture for data communication between data sources and data destinations via network nodes and at least one data concentrator. According to the invention the nodes ( 2, 4 ) are conceived to communicate with a data concentrator ( 1 ) in both directions either via a permanently operative network ( 8 ) in the multihop mode or via an occasionally operative network ( 5 ) in wireless connection with mobile user nodes ( 6 ) in the nomadic mode. Means for commutation are provided to detect faulty multihop nodes and to activate nomadic nodes instead until the fault disappears, in order to maintain the overall functionality of the network. Moreover the network according to the invention allows the data collected by mobile users to be shared with other mobile users, thus forming a peer-to-peer network.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/135,167 filed Dec. 19, 2013, which is a continuation of U.S.application Ser. No. 12/158,412, filed Jun. 20, 2008 (now U.S. Pat. No.8,644,131), which is a national stage filing under 35 U.S.C. 371 ofInternational Application No. PCT/EP2006/012291, filed Dec. 20, 2006,which claims priority from European Patent Application No. 05028181.5,filed Dec. 22, 2005, which are incorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

BACKGROUND OF THE INVENTION

The present invention refers to data communication networks adapted tointerconnect multiple data sources and data receivers.

The opportunistic exploitation of mobile users moving in a certain areaand being equipped with wireless digital devices of high performance interms of computing and memory, and able to collect, to process and toshare environmental data collected via a large amount of low-costsensors located in outdoor environments is currently of high interest inthe research field of Situated Autonomic Communications. It has beenrecognized that such nomadic approach has the potentiality to pave theway to the induction of large-scale deployment of location/context awareapplications and services for the benefit of both private and publicusers. Furthermore such communication paradigm solves the well knownscalability and cost problem inherent with multi-hop routing-basedarchitectures.

The European patent applications EP 05001930.6 and EP 05008909.3 of thepresent applicant aim at a novel approach able to address thesechallenges. Nature and society exhibit many instances of systems inwhich large populations are able to reach efficient equilibria and todevelop effective collaboration and survival strategies, able to work inthe absence of central control and to exploit local interactions. Thepresent invention intends to provide a fully integrated network andservice environment that scales to large amounts of heterogeneousdevices, and that is able to adapt and evolve in an autonomic way.

The subjects of the European patents cited above overcome deviceheterogeneity and achieve scalability via an autonomic and localizedpeer-to-peer communication paradigm. They evolve to adapt to thesurrounding environment, just like living organisms evolve by naturalselection. Network operations are driven by the services, providing anad hoc support when and where needed to fulfill user requests. Securityissues are considered as a fundamental part of the services themselves,representing a key ingredient for achieving a purposeful autonomicsystem. The network becomes just an appendix of the services which, inturn, become a mirror image of the social networks of users they serve.This people-centric paradigm breaks the barrier between serviceproviders and users, and sets up the opportunity for “mush-rooming” ofspontaneous services, therefore paving the way to a service anduser-centric Information and Community Technology revolution.

The present invention intends to resolve the problems due to theemerging trend towards pervasive computing and communicationenvironments, i.e. the large number of networked embedded devices. Suchdevice possesses sensing/identifying capabilities, making it possiblefor user-situated services to interface directly with the surroundingenvironment, entailing the possibility of introducing radically novelservice, able to enhance the five senses, and the communication and toolmanipulation capabilities of human beings.

The embedded devices must possess computing and (basic) communicationcapabilities, having the potential to form a massively larger networkedsystem, orders of magnitude larger than the current internet. Thecomplexity of such environments will not be far from that of biologicalorganisms, ecosystems and socio-economic communities.

Traditional communication approaches are ineffective in the context,since they fail to address several new features: a wide heterogeneity innode capabilities and service requirements, a huge number of nodes withconsequent scalability issues, the possibly high node mobility and themanagement complexity.

The network architecture according to the present invention resolves theproblems cited above and provides a structure which is based on atrade-off between the known state of the art concerning multihop routingand the content of the earlier EP applications cited above of thepresent applicant, called here-after nomadic approach.

According to the invention, the network architecture for datacommunication between data sources and data destinations via networknodes and at least one data concentrator is characterized in that thenodes are conceived to communicate with a data concentrator in bothdirections either via a permanently operative network in the multihopmode or via an occasionally operative network in wireless connectionwith mobile user nodes in the nomadic mode, and that means forcommutation are provided to detect faulty multihop nodes and to activatenomadic nodes instead until the fault disappears, in order to maintainthe overall functionality of the network.

For details and variants of the networks according to the inventionreference is made to the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing will be apparent from the following more particulardescription of example embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingembodiments of the present invention.

FIG. 1 shows schematically a network according to the invention.

FIG. 2 shows schematically the intercommunication between a dataconcentrator 1 and two nodes 4 initially in the nomadic mode.

FIG. 3 shows schematically the intercommunication between a dataconcentrator 1 and nodes in nomadic or multihop mode for serving amobile user 6.

FIG. 4 shows schematically the intercommunication between a dataconcentrator 1 and multihop nodes in case of a malfunctioning node.

DETAILED DESCRIPTION OF THE INVENTION

A description of example embodiments of the invention follows.

As shown in the exemplary drawings wherein like reference numeralsindicate like or corresponding elements among the figures, exemplaryembodiments of a system and method according to the present inventionare described below in detail. It is to be understood, however, that thepresent invention may be embodied in various forms. Therefore, specificdetails disclosed herein are not to be interpreted as limiting, butrather as a basis for the claims and as a representative basis forteaching one skilled in the art to employ the present invention invirtually any appropriately detailed system, structure, method, processor manner.

Referring now to FIG. 1, the network is organized around a dataconcentrator 1 as a wireless, permanently connected cluster oftransceiver devices and nodes 2 in the multihop mode, associated with adata source 3 (or a multiplicity thereof), wherein the information movesamong said nodes towards the data concentrator 1 by following themultihop approach. In addition to such clusters, a certain number ofnodes 4 are available, which are not connected to said clusters. Suchnodes operate independently from each other and provide theirinformation via occasionally connected network extensions 5 topassing-by mobile users 6 on a polling basis. Devices of mobile users 6carry said data, after having picked them up, until the users approach adata concentrator 1. It is further possible that the users might sharethe collected data among themselves (whenever they encounter mobileusers along the travel) via peer-to-peer communications.

All data collected by any data concentrator (only one concentrator 1being shown) will be forwarded, raw as they were collected or modified,after some preliminary elaborations, to an operational center 7 wherethe collected data is analyzed.

Depending on the kind of situation, it will be perceived at theoperational center and adequate case-specific procedures will beeventually activated.

The network according to the invention is based on two distinct networksmerged in an integrated architecture: In the multihop mode, nodes 2 finda wireless path through other nodes (not shown in FIG. 1) via apermanently operational network 8 to a data concentrator 1. Techniquessuch as data aggregation or particular architectures could be used tooptimize the number of messages sent (thus reducing the powerconsumption of the nodes). The activity of the network 8 is managed bythe data concentrator, scheduling the tasks of nodes (basically collectdata from environment).

In the nomadic mode data is collected by a node 4 independently withoutcommunicating with other nodes. When a mobile user 6 is sufficientlyclose to the node, the latter sends via the occasionally connectednetwork extension 5 to the user 6 all the data collected. The mobileuser 6 then moves in an area where there could be other mobile users: Ifit crosses one of them, it shares “on the fly” all the collected data.Every time a mobile user 6 reaches a data concentrator, it forwards toit all the data it has collected during its travel.

The network architecture according to the invention is composed of fourdifferent kinds of devices as shown in FIG. 1. Their respective linksare represented according to the UML standard as follows:

Lines terminating with an arrow-like triangle (see static network node11) signify an inheritance relationship or hierarchical dependencybetween nodes.

Lines terminating with a white lozenge mean an aggregation relationship.The two objects linked by this lozenge are logically grouped together.

Lines terminating with a black lozenge mean a composition relationship:Each instance of the object close to this lozenge is composed by acertain number of instances of pointing object.

The symbol comprising a square rectangle (such as between the nodes 4and 6) signifies a physical interface (one of them bearing the referencenumeral 9). The objects linked in this manner can communicateunidirectionally, the communication direction being defined by the arrowat the end of the line.

The notations “1”, “. . . N” and “0 . . . 1” along certain link linesdefine the number of instances with which an object cooperates, namelywith exactly one, at least one, or at most one instance.

The essential elements of the network according to the invention willnow be described:

Nodes 2 and 4 comprise each at least a transceiver, adequate computercapability, a memory and at least one component acting as the datasource. They operate either in the multihop or the nomadic mode. Bothare derived from the conceptual static network node, which is intendedto cooperate with at least one data source 3 and one or more short rangetransceivers.

Mobile user nodes 6 are mounted on mobile units which move across thearea where the architecture is deployed. It can collect data from nodes,share them with other mobile users and then forward them to the firstdata concentrator met during its movement.

A data concentrator 1 is able to communicate via interfaces (blackdouble arrows in FIG. 1) with all the other kinds of devices forming thenet. It organizes the communication with them and participates therewithas an active element.

An operational center 7 is the final destination of all informationcollected by mobile users. It sends its queries to the data concentrator1 and can handle the large amount of data that it receives as answerfrom them.

Finally short and long range transceivers 10 and 12 are foreseen fortransmitting data within the network.

The partial replacement of the classical network infrastructure with themobility of mobile users which collect and share data offers thesolution to the technological challenge of ensuring connectivity.

The nomadic mode is the default mode for every node, but if a messageoriginally sent from a data concentrator 1 arrives at a node in thenomadic mode (directly or indirectly), the node commutes to the multihopmode, self-organizing to join the cluster of that data concentrator andinvolving other eventual nodes adjacent to it and not yet commutated.

If a malfunction in the net makes the data concentrator 1 no morereachable by a certain node in multihop mode, this node commutes to thenomadic mode. So if an adequate number of mobile users 6 grants thecoverage of all nodes, data collection proceeds possibly slower butsuccessfully in every active node, and the loss of data is limited tothe fallen or malfunctioning nodes.

FIG. 2 shows the data flow between a data concentrator 1 and two nodes 2and 4. After an initialisation phase (not shown) both nodes are in thenomadic mode. Periodically the data concentrator 1 sends a querymessage. A node receiving such a message which is in the nomadic modecommutes to the multihop mode and then forwards the received message.

If a node receives no acknowledgement within a given delay (“time out”T.O.) for the forwarded query (see node 4), it sends an answer messageto the node from which the query message came. If a node receives ananswer message, it integrates this message into its collected data andsends it to the node (or to the data concentrator as the case may be)that had sent the query message.

FIG. 3 shows the data flow between the data concentrator 1, a node 2 inthe multihop mode, two nodes 4 and 4′ in the nomadic mode and a mobileuser 6. Periodically every user sends a poll message. If a node in thenomadic mode receives it, this node transmits to the user the data whichit had collected. In this example it happens at the instant Tx betweenthe user and the node 4′ and at the instant Ty between the user and thenode 4.

If a poll message sent by the user is received by a node 2 in themultihop mode, it will be ignored by this node. This happens here at theinstant Tz.

Finally if the poll message emitted by a user is received by a dataconcentrator, the latter replies with a data dump request message thussignalling to the user the presence of the data concentrator.Consequently the user sends to the data concentrator all the collectedinformation which it had gathered since it met the previous dataconcentrator.

FIG. 4 applies to the data transfer in case of a malfunctioning node 2′in the multihop mode: Due to the malfunctioning node 2′ thecommunication between node 2″ (in the multihop mode) and its relateddata concentrator is broken. Consequently, since the node 2″ has notreceived any query message within a given space of time (T.O.), the node2″ itself commutes to the nomadic mode and waits for a user 6 in orderthat the latter collects its information at the instant Tx and deliversit at the instant Ty to a data concentrator (not necessarily the one towhich the node is associated, but the one which the user approachesfirst).

A node that has been commuted to the nomadic mode after having lost theconnection to a data concentrator may commute again to the multihop modewhen a query message arrives there as described on the basis of FIG. 3.

A single mobile user 6 collects data from low cost sensors, transportsthe data during his movement and exchanges/shares them with thecommunity of mobile users populating that area. Mobile users may collectdata from the concentrator 1; integrating their knowledge of thesurrounding environment with the one collected by the multihop subnets.As compensation for its help in collecting, transporting and sharinginformation, a mobile user receives continuously updated informationrelated to a wider geographical service coverage than the one it canobtain just acting alone. At the same time, local administrations orthird parties may take advantages from the existence of this service inorder to improve the existing public/private services or to offer to thecitizens new kinds of services.

A further advantage of the network according to the invention over thestate of the art resides in the fact that it helps to obviate to theproblem of partitions of the permanently connected net (consequence ofmalfunctioning nodes), taking advantage of the ability of the mobileusers to diffuse data.

What is claimed is:
 1. A method for transferring data using a mobiledevice in a network including a network device and a node operating inone of two operating modes, the method comprising: sending a first pollmessage from the mobile device; receiving at the mobile device, inresponse to a node operating in one of two operating modes receiving thefirst poll message, collected data comprising data collected by the nodewhen the node is operating in a first operating mode; sending a secondpoll message from the mobile device; receiving, in response to thenetwork device receiving the second poll message from the mobile device,a request for a data dump from the network device at the mobile device;and transferring the collected data from the mobile device to thenetwork device, in response to receiving the request for a data dump. 2.The method according to claim 1, wherein the network device is a dataconcentrator device.
 3. The method according to claim 1, wherein whenthe node is operating in a multihop mode, the poll message is notresponded to.
 4. The method according to claim 1, wherein the firstoperating mode is a nomadic mode.
 5. The method according to claim 1,wherein the first poll message and the second poll message are sent atthe same time and comprise the same poll message.
 6. An apparatus totransfer data, the apparatus comprising: a processor; a memory coupledto the processor, the processor configured to: send a first pollmessage; receive, in response to a node operating in one of twooperating modes receiving the first poll message, collected data fromthe node, the collected data comprising data collected by the node whenthe node is operating in a first operating mode; send a second pollmessage; receive, in response to a network device receiving the secondpoll message, a request for a data dump from the network device; andtransfer the collected data to the network device, in response toreceiving the request for a data dump.
 7. The apparatus according toclaim 6, wherein the network device is a data concentrator device. 8.The apparatus according to claim 6, wherein when the node is operatingin a multihop mode, the poll message is not responded to.
 9. Theapparatus according to claim 6, wherein the first operating mode is anomadic mode.
 10. The apparatus according to claim 6, wherein the firstpoll message and the second poll message are sent at the same time andcomprise the same poll message.